Facial Rigging: Where to Begin

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Hi,

I completed several rigging in Houdini. I am now moving with facial rigging and I do not know where to start from. I did some some search and I saw some people talking about blend shapes: (Duplicating the head geometry). At the same time I saw this interesting article in Sidefx http://www.sidefx.com/docs/houdini/character/facialrigging.html [www.sidefx.com] . It is about using Morph tool to create your the facial rig. At this point, I have no idea about facial rigging and how to start. I am attaching my hip file which I am working on in case someone would like to walk me through the process and help me understand it.
Image Not Found
Edited by John31 - May 26, 2019 17:17:33

Attachments:
Testing Facial Rig.hiplc (8.6 MB)

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Ok, this is some progress I made so far. Houdini has it is own Facial Auto Rig System, which seems to be very interesting if you know what you are doing. The system build some blend shape using a cage shape that you can project into the face. The system is very easy to use, but when it comes to the caging process and moving the markers around the face, it would take a lot of time. I have spent almost three hours re-placing the cage markers in the face without a success. You will need the cage to be well projected in order to Houdini to generate a Mask. Again, I have failed in the Cage stage because of re-placing the markers. It would be easier if the cage blended shapes can be controlled via Soft selection tool, edges, points…etc for the projection purposes only. Then markers can be generated at later stages. Shout out to @goldfarb, if you are reading this, I read somewhere that you are preparing a facial rig tutorial alongside with weight capturing tool tutorial, please kick it in and let us have these tutorials. The reason I am saying this is because rigging the rest of the bones in Houdini is almost like 15 mins work now. Thanks to your hard work in your rigging tutorials!




The next approach I have with facial rigging is to generate the blend shapes myself.

References I used:

https://www.sidefx.com/docs/houdini/pypanel/autorigs.html [www.sidefx.com]

Attachments:
Facial Rig.png (1.6 MB)
Facial Rig - Caging.PNG (1.3 MB)

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Moin,

I admit that I cannot follow your thought process - but my assumption is that it might help you to familiarize yourself with how a face deforms in the real world (bone structure, pivots, areas of influence/muscle/fat). Then gather some fundamental understand of what a weight-map driven deformation (using “bones”, as in 3d-control-elements, or joints and “influence maps”) versus blend-shapes/aka “morphs”. Both approaches have advantages and disadvantages, often a mixture of them is used.

This isn't much of a hands-on help, I know, but it seems to me like you want to go your very own way, so the best I can throw in the mix is some “understand the basics first” line of thinking …

Marc

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Moin Marc,

First post was a demostration of my thoughts about facial rigging since I have not done any before. There were too many words and terms involved but the most I found being used is “blend shape”. However, next post I found out is that Houdini has a facial rigging system, I described my expereince with it for today. And as a begginer,I thought that videos tutorials are required.

My applogize for any confusion.

Prost,
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Hi,

no apologies needed

I simply thought that maybe it would help if you first looked into basics before trying to apply “just any” way of rigging (and animating) a face. (As for video tutorials: I used to create those until about last year, but I realized that most video tutorials don't show you WHY something is done, just THAT it is done, so most people don't really learn that much from following a video, so I stopped making them and surely stopped watching them )

In my world “blend shape” = Autodesk terminology = morphs in other worlds = same thing. Basically you store (linear) alternative positions for points and “blend” between the points' original positions and those “morphed” to get to a different “shape” (there you go, everything in one sentence).

Again, from my point of view understanding WHAT does what, why something does what it does and then think about what you want to do yourself: Realistic motion (probably not so much considering the very low resolution mesh you screencapped) or cartoony/game-style animation, basic expressions or fine detailed “acting” etc.

Marc

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Thank you Marc for your reply and clarfications. I am still learning too many things and moving out from Autodesk has its affect on me. I am watching Maya tutorial and trying to convert the concept in Houdini. I know it is hard, but guess what I got the facial system work in Houdini after all and after too many attempts in my own, The purpose is purley learning I have nothing in mind that'a why I did not care about the mesh resoultion.but it will be defintley the start of exporting to UE4 not for game but for video productions.

To be honest, I am amazed with the system of facial rigging in Houdini, despite the clusterd results I got after weight capturing but the system is really animation friendly and would blow up other packges in the future. I will try to post the progress and some pics after cleaning the weight.

One more thing, I watched your videos. Your comparison with Modo is my favourite.

Thx,
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I am still practicing on the face rigging system in order to get it accurate. But today I received this Error message after generating the rig:


Attachments:
Error Message.png (140.3 KB)
Error Message 2.png (750.3 KB)

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The yellow marks above the bonedeform most likely give you the hint - you may have to restash (“stash” node) your data because you changed something “upstream”.
Houdini's sometimes odd “invalidation” logic is one of the hurdles to overcome (and in my eyes one of the biggest ones in general).

Marc

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the Stash SOP needs to be cooked
click on Stash Input
Michael Goldfarb | www.odforce.net
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Thanks Marc and Goldfarb. The problem I replaced File node with Object merge.
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Still playing with the basic Auto face rigging. I think I need some advice with placing the eyes markers. below are the pictures of the results and the way I placed the markers:

Attachments:
Placing Eyes Marker 3.png (895.3 KB)
Placing Eyes Marker 2.png (744.8 KB)
Placing Eyes Marker 4.png (973.3 KB)
Placing Eyes Marker 5.png (93.1 KB)

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it's difficult to see exactly what is going on - can you upload your file?
Michael Goldfarb | www.odforce.net
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Attaching the file.

Attachments:
untitled.hiplc (6.3 MB)

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open an Autorigs python panel and drag+drop the hda into it
the panel should load the settings for the asset

the way the eyelids work is
the green dots are where the tips of the eyelid bones will be
the upper and lower red dots are top max open and lower max open
the centre red dots are where the lids will close - you can adjust this so the eyes will close higher or lower relative to the center of the eye

I've made some adjustments to better capture the geometry - you'll need better geometry I think for these eyes, there isn't much there.

hope that helps - let me know if you have any questions

Attachments:
untitled1.hiplc.zip (1.9 MB)

Michael Goldfarb | www.odforce.net
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Michael,

Thanks for the help and explanation. Any chance to resize to the markers to make it match the eyelids ? with the current settings I see the controller is closing the eye lens instead of the lid. The geometry is taking from Daz3d, do you suggest that I shall bring it in with eyes half closed and mouth half open ?
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You need to separate the individual body parts, here: Separate the eyeballs from the head. Obviously, you do not want the eyeballs to be deformed by a weight map that is applied to the head/eyelids. “Group away” the eyeballs/lenses etc. and only apply deformation to “!my_eye_group”.

Marc

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Marc,

I did group the eye balls, but not sure how to exclude them from auto rig deformation.
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I moved out from face auto rig to creating my own blend shapes in Houdini. Nothing wrong with the tool really but I need more training on how to adjust things in the auto facial rig system. I am pretty sure it is a game changer in the industry.

I am satisfied with the results of blend shapes in Houdini and I will be moving on to test the blend shapes in MB for further testing with facial mocap.

Thanks you Marc and Goldfarb for the support and comments.

Attachments:
Blend Shapes.PNG (2.7 MB)

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Exporting to MotionBuilder did not work for me, blend shapes were recognized but not moving for some unknown reason. I am not sure If I will be able to animate lip sync at this point. Facial rigging is frustrating topic for me, so I decided to stop my experiments with facial rigging till the release of further tutorials.


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Hmm … it is, of course, your decision how you spend your time.

I would like to repeat that, in my experience, making oneself familiar with the fundamental workings of a technique one is about to use/learn often helps in overcoming obstacles. You seem to be saying that you “give up” because your efforts in Houdini don't give the results you expect in a completely different tool. To me, that looks like you are mixing two independent problems, only to make things as hard as possible for yourself, instead of learning ONE tool at a time.
There are people who study their trades for years, some say that learning is “a life long thing”. Waving a white flag after a couple of days for one could not make two different tools magically do “the right thing” all by themselves might be a bit short-sighted.

What I take out of this discussion is: It was the right thing to stop producing free video tutorials. People who want to LEARN don't need “this is how you do this one particular thing” tutorials, they need fundamental, basic, complete and highly detailed documentation.

Marc

Software Sewers Service (aka Pipeline Problems Solver)
https://vimeo.com/marcalbrecht [vimeo.com] - https://www.marc-albrecht.de [www.marc-albrecht.de]
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